Excessive low frequency noise may be experienced inside a machine cab due to excitation from internal combustion engine exhaust. U.S. Pat. No. 6,241,044 discloses various embodiments of exhaust mufflers. However, it has been found that exhaust noise excitation can result can result in significant sound levels in an operator cab, which can be not only bothersome to the operator but hazardous. Typical muffler designs are tuned to a single frequency or a narrow range of frequencies. However, it is desirable for a muffler to provide noise attenuation across a range of frequencies, and in a particular application, also provide low frequency (<250 Hertz) attenuation as well.